Perl treats "undef" as zero (or the empty string) but only after emitting a warning.

Thank you very much, you said it yourself.

If you called your bank and asked for balance and they said "I don't know; the computer system is down for maintenance and I can't look it up right now", then that would be getting a balance of "undefined" (or "unknown"). This is much different than a balance of "zero". Surely you can see that.

Ohh no, please don't play with words to convince me that the words "undefined" and "unknown" mean one and the same thing. They are just not equivalent. If I deposited £200 in my account last week and my bank told me today they couldn't tell me the balance in my account because of some issue preventing them doing so, does not mean the value is undefined, it clearly is, it's just that there are no means to determine it's value at the present time, it is however unknown, the two terms are disparate and do not mean the same thing.

So it appears that you do have a problem understanding a couple of those terms.

No, I just don't happen to let the semantics of those terms within the scope of a few computer programming languages make me see square. A dictionary is enough to tell me that all these terms i.e. zero/undefined/void/null/empty amount to essentially the same thing i.e. "something without significance or value".

But now. what i really have a big problem understanding is - You seem to have accumulated tremendous XP here on PM, there is no better candidate to stand up for the nit-picking, pedantic, make-perl-matlab community to voice their concerns. Why you don't try and convince Graham Barr or P5P to do something about this really trivial non-issue? The XP gained here has to count towards something constructive after all, doesn't it?

perl -e '$,=$",$_=(split/\W/,$^X)[y[eval]]]+--$_],print+just,another,split,hack'er

In reply to Re^9: List::Util::sum() and empty lists... (undefined) by Firefly258
in thread List::Util::sum() and empty lists... by blazar

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.